I use Organic B and Iguana Juice for my orchids which has proven to be an excellent in feeding orchids. Even I found that B52 fertilizer booster, with essential b vitamins and hormones, increases the plant metabolism of orchids and strengthen their immune systems.

Would it be OK if I threw a slight twist in this thread - still on-topic, of course?

I think when it comes to meeting the nutritional needs of orchids, the formula is not critically important, and "less is more".

If your feeding regimen provides the macronutrients and a decent array of micronutrients, and you feed frequently, in small doses, your plants will be fine.

I prefer the idea of "continuous feeding" - i.e., almost- if not every watering - as it seems to me that replicates nature, where the food supply is meager, but pretty much ever-present. Add to that the fact that while plants do store some nutrient ions and can relocate them to newly-growing tissues, other mineral ions cannot be, so it's important to keep up a steady supply as the plants grow. Not only that, but by feeding at every watering, as I do via a metering pump, I can be lazy and "just water" without giving it a second thought. (I have fed at every watering for the past 25 years - unless the stock tank runs dry.)

Plants, in general, do not need much phosphorus, and I have been learning a few things that are specific to epiphytes that I find very interesting. One is the fact that in their natural biospheres, there is also very little potassium, and that excessive potassium can lead to a reduction in the uptake of other critical ions, namely calcium and to a lesser extent, magnesium. When that happens, plants can become more susceptible to fungal attacks. Apparently though, as long as the supply of the last two is adequate, excessive potassium is not a major issue, short-term.

I really like the so-called "MSU" fertilizers, as they provide all of the nutrients and maintain a low amount of phosphorus (the excess is considered a pollutant, and is seeing some regulatory attention here in PA), but is still high in K. A few folks I know have experimented with feeding a combination of only calcium nitrate and magnesium sulfate, and after almost a year of that, still seem to have healthy plants.

I went to Bill Argo, the developer of the MSU formulas, and he derived a "K-Lite" fertilizer (12-1-1) that also contains the micros for us, and there are about 75 people (mostly in the US and Canada, but also Norway, Sweden, Holland, Germany, France, Italy, South Africa and Israel) that have been using it. I started late last December, and am not seeing any symptoms of deficiency.

The concept is that most media - bark and CHC particularly - preferentially build up potassium with time, so even if your fertilizing regimen has plenty of calcium, the buildup in the medium throws off the balance. By providing a low level to start with - certainly well within the range they would see in nature - you slow the buildup process.

I think when it comes to meeting the nutritional needs of orchids, the formula is not critically important, and "less is more".
If your feeding regimen provides the macronutrients and a decent array of micronutrients, and you feed frequently, in small doses, your plants will be fine.

The concept is that most media - bark and CHC particularly - preferentially build up potassium with time, so even if your fertilizing regimen has plenty of calcium, the buildup in the medium throws off the balance. By providing a low level to start with - certainly well within the range they would see in nature - you slow the buildup process.

Thanks! This is actually how I've been trying to go about it all along...mostly because I don't want to have to keep tabs on when I fed which orchid last! And I always water first, then fertilize, even with the weaker mix. But the root burn was totally mystifying me.

But now that I think about it, I think the root burn was actually caused by me mixing Superthrive in a spray bottle with water and spraying the surface of my potting media with it daily (along with any roots that were on the surface). Someone had suggested spraying the top of the bark with a Superthrive/water mix to help with humidity and also allow for more nutrient absorption, and it was right around then that I noticed my roots showing some damage. The other giveaway that the Superthrive was the culprit was that the roots down inside the media are fine...it was just the aerial ones and the ones on the surface that got burned....and those are the ones that got sprayed directly with the Superthrive water. Perhaps I mixed it too strong. Anyway, I stopped doing that a while ago anyway, so if that was the cause, I should be root-burn free from here on out.

My biggest concern with finding the "right mix" was caused by one particular Green Lantern dendrobium that just seemed miserable no matter what I did. Some of its leaves turned yellow and fell off, and it didn't seem to be growing at all. After a few months I contacted the seller, who said that particular den is a heavy feeder that needs calcium, at which point I realized my fert has none. My species phals also seem to be very, very lazy. My catts, dens, vandas, oncids, and paphs are all growing well, but my species phals are just sort of sitting there. I have a phal Mariae that has had the same spike on it for months but has done NOTHING. I'd be doubtful if the spike has grown a centimeter since I've had it.

So I thought perhaps there might be a better fert mix out there to "kick start" my phals, since my regular regimen of Superthrive alternated with weak fertilization just doesn't seem to be doing much.

As far as the potassium buildup concern...I don't know much about chemistry, but wouldn't repotting solve that? I mean, if we are repotting our orchids every couple of years, wouldn't the potassium buildup be a non-issue once the orchid was repotted? I'm assuming most of us replace our media when repotting...at least I do. If you're keeping the same media and just putting the plant in a larger pot, I can see the potassium continuing to be an issue, but if you're replacing media that has broken down with brand new media, wouldn't that effectively "reset" the chemicals present in the mix?

I don't think a new fertilizer is going to make any difference in how fast your species phals grow. I've experienced the same phenomenon, most phal species do not grow with same vigor as the hybrids. Some of them grow very slowly in fact.
Also I don't think that Superthrive is meant for daily use. It's a very potent product and growers that I know, who use it, use a very small amount, once a month.

I don't think a new fertilizer is going to make any difference in how fast your species phals grow. I've experienced the same phenomenon, most phal species do not grow with same vigor as the hybrids. Some of them grow very slowly in fact.

Ahhh, well, one can certainly dream. I'm going to order some fish emulsion too that some orchid growers love...maybe that will do something for the phals. Thanks for sharing that yours are slow-growing too...at least now I know mine aren't the only ones that seem to just be "leafing around."

Also I don't think that Superthrive is meant for daily use. It's a very potent product and growers that I know, who use it, use a very small amount, once a month.

Thanks. At the time there was a debate going on in a thread about whether SuperThrive provided any visible benefits to plants. I said I was certain that it did, because I had a couple of plants that I nursed back from the brink of death using ST as a boost. But others said they didn't notice any difference at all. Then one gal popped in and said she had a whole bunch of seedlings that she misted daily with Superthrive. She said her seedlings were "taking off" and that she loved using the SuperThrive mist. Then I tried it and I noticed root burns and some foliage burns as well...so I stopped. I'm not sure how weak she mixed hers...but it must have had next to nothing in it for seedlings to tolerate daily misting with ST. Anyway, at least now I know what NOT to do! Thanks for the advice, Jeff!

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